Speaker cone



Aug. 6, 1935. R, R. DU PUY SPEAKER CONE Filed Nov. 22, 1929 Fly.

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. TTO-RNEY Patented Aug. 6, 1935 UNITED STATE-S PATENT OFFICE SPEAKER CONE Richard R. Du Puy, St. Paul, Minn.

Application November 22, 1929, Serial No. 409,147

2 Claims. (01. 179-1155) My invention relates to improvements in radio loud speaker cones, ofthat type wherein a comparatively flexible cone, as of paper, is employed.

My invention has for its object particularly to provide means for constructing the cone with respect to vibration to prevent loosening and breaking of attached parts, etc.

This and other objects of my invention will be more specifically set forth in the following description and the accompanying drawing, wherein:

Figure 1 is a view in front elevation of the cone fitted with my improvement.

Figure 2 is a sectional view on line 22 of Figure 1; and

Figure 3 is a plan view of the vibratory center for the cone.

In the drawing, A represents a cone of the usual construction, preferably made of paper, and having the usual cylindrical throat portion 2. Surrounding the throat portion 2 is a voice coil 3. In carrying out my invention, the voice coil 3 is connected to a source of electrical supply, as a transformer, by the following means:

Secured in the cone adjacent to the throat, as shown in solid lines in Figure 1, or adjacent to the outer edge of the cone, as shown in dotted lines in Figure l, are two spaced apart eyelets 4 and 5. A conducting wire 6 leads from the transformer, not shown, to the eyelet 4, being secured in position underneath the eyelet 4, and a return wire I is similarly connected from the eye-,

let 5 to the voice circuit. Wires 8 and 9 lead from the eyelets 4 and 5 to the voice coil 3, the wires 8 and 9 being preferably glued down to the face of the cone. If desired, the wires 8 and 9 may be extended down to a point adjacent the lower edge of the cone, as indicated at 9a and 9b and secured to eyelets 4a and 4b.

Across the throat 2 of the cone, I provide a flexible diaphragm In, as of leather, the edges of the diaphragm Ill being secured as by gluing underneath the cone adjacent to its throat, as

shown in Figure 2. The diaphragm I0 is formed with a central opening H to permit fastening of the member In to a portion of the loud speaker mechanism, not shown, in a well known manner to centralize the cone with respect to other portions of the loud speaker.

An annular mounting ring I2 is constructed of sheet material such as stiff cardboard or metal, the opening therein being slightly larger than the diameter of the lower end of the cone A. An annular strip l3 of flexible material, preferably soft leather, is secured between the ring I2 and the cone A. The ring I2 is provided with openings I4 to permit fastening the cone to the loud speaker frame in a customary manner. This construction, combined with the flexible leather member I0, permits the cone to float more or less freely within the limits of movement of the flexible members In and I3 at the same time keeping the cone centralized with respect to its axis.

As it will be understood, the coil 3, when energized, acts in the usual manner to vibrate the cone and transform the pulsations of the voice circuit into sound waves.

By means of the features of construction shown and described, I permit full, undistorted vibration of the speaker cone, and insure against the loosening and breaking of attached parts, and greatly increase the efficiency and life of the cone. In the ordinary construction of cones of this character, the method of electrical connection to the voice coil is such that after continued use there may be a material loosening in use of the attached parts, and loosening and breaking of the central diaphragm, which diaphragm ordinarily is of open-work paper. Such loosening or breaking of parts, of course, destroys the tone of the speaker.

With my method of eyelet arrangements secured within the cone wall itself, it is possible to secure a very rigid connection between the eyelets and the voice coil, with the wires leading outwardly from the eyelets remaining loose and away from the surface of the cone, but rigidly held in anchoring position in connection with the cone. The diaphragm l0 permits free, undisturbed vibration of the cone without breaking or crystallizing, and cooperates with the method of wire attachment to the voice coil in bringing about the maximum amount of cone efficiency.

I claim:

1. A speaker cone having a coil mounted near the apex thereof, conductor means leading from the coil and secured throughout their lengths to the-surface of the cone, rivet means penetrating the cone and riveting the ends of said conducting means to the cone, second conducting means having an end thereof riveted to the cone by the same riveting means as that holding the coil conductor and being free of the surface of said cone except at the points of connection therewith, and a pair of soft leather annular members connected to the cone in spaced parallel planes parallel to the base to support the cone against lateral displacement and to permit free vibration in a direction parallel to its axis.

2. A device of the kind described, comprising a magnet providing an annular magnetic field, a winding disposed in said field, a diaphragm operatively connected to said winding to be vibrated thereby, electric terminal members projecting through the wall of said diaphragm, and electrical conductors connecting said terminal members with said winding.

RICHARD R. DU PUY. 

